The present invention relates generally to a socket assembly used for electrical plugs. More particularly, the present invention relates to self-closing safety socket assembly uses a plate and a spring in cooperation to facilitate the insertion and the subsequent removal of an electrical plug into and out of a socket. The present invention is particularly suitable for connection with extension cords.
Safety sockets capable of self-closure are known. Two examples of these sockets are U.S. Pat. No. 2,820,842 to J. V. Meistrell and U.S. Pat. No. 4,600,258 to Hu. In '842, a shutter is provided in cooperation with a spring to close or block undesired objects from entering the socket. In '258, a partition board is provided in cooperation with a spring to close or block the entrance of the socket. For normal insertion of a plug through the slots, the shutter or the partition board has to be displaced sideways, i.e., by moving the shutter by the plug in Meistrell's patent or by externally pulling the partition board in Hu's patent. In either case, an external lateral force is required to allow insertion of the plug. A disadvantage resulting from the requirement of an external lateral force is that when the safety socket is used in connection with a portable power line or extension cord (i.e., the socket is not fixed), it will be difficult to insert the plug if one hand is unavailable to secure the socket while the other hand insert the plug.
To facilitate the insertion of a plug while still retaining a safety factor, the present invention discloses an improved socket assembly comprising a plate means which has one side wall for each of the plug's guiding slots tapered sideward or sideways. The side wall is tapered so that an insertion of the plug will move the plate means sideways. In this manner, an insertion of a plug into the socket assembly in accordance with the present invention is simple and direct, without the need to apply an additional lateral force prior to or the necessity to hold the socket stationary during this procedure.